1. Field of the Invention
The present invention is related with an optical disc reproducing apparatus. Especially, it is related with an optical disc reproducing apparatus having means for discriminating an optical disc, such as a CD (Compact Disc), and a partial CD-R (CD Recordable) which is an optical disc of write once read many type in the middle of writing.
2. Description of the Related Art
There is a CD (Compact Disc) as an optical disc which records sound information etc. An example of such a CD is shown in FIG. 1.
As shown in FIG. 1, in a CD 104, a lead in area LIA in which index information of the record information is recorded, a program area PA in which the actual music information etc. is recorded, and a lead out area LOA which indicates the end of the program area PA, are sequentially formed from the inner circumference of the disc of the CD 104.
The signal recorded on the optical disc is the digital signal modulated by EFM (Eight to Fourteen Modulation), which includes sub-codes, such as a time code (time information), other than main codes (main information), such as music information. Index information called TOC (Table Of Contents) is recorded in the lead in area LIA. The total number of the pieces of the record information recorded in the program area PA of the optical disc (for example, the total number of musics), the total recording time (for example, the total performance time), etc., are recorded as a sub-code in the index information. Music information etc. as a main code is recorded in the program area PA. In addition to this, the track number (TNO) which indicates the piece number of the record information (for example, music number), the recording time from the track start (P-TIME: for example, the performance time of the music), the total recording time measured from TNO=1 (A-TIME: for example, the total performance time), are recorded in the channel Q data of the sub-code. The lead out code which indicates it is the lead out area, is recorded in the lead out area LOA.
A CD player, which reproduces the record information on the above mentioned CD 104, is constituted to perform the following operation. Namely, when the CD is set, the CD player moves a pickup, which is an optical head, to a predetermined initial position. After this, it performs a set up (SET-UP) to be in the state where the information reading is possible, by rotating the CD. When the set up is completed, it reads the TOC information from the lead in area LIA. Generally, the access information such as a track number (TNO) of the information record piece, which is recorded in the program area PA, is included in the TOC information, so that the access control of the indicated information is performed by storing the access information.
By the way, the CD which has a record format mentioned above, is a record medium only for reproduction. However, a CD-R, which is a recordable optical disc of write once read many type, to enable writing of information, while employing the same format as the CD, is desired.
The record format standard of this CD-R is unified by the standard so called "orange book", which is based on the CD format standard (which is called "red book").
As shown in FIG. 1, the disc of this CD-R, is classified into three categories (CD-R 101 to 103), according to the recording state, as following.
(1) A blank disc i.e. a CD-R 101 in FIG. 1, which is in the non-recorded state where information is not yet recorded (it is referred as a "blank CD-R", hereinbelow).
(2) A disc i.e. a CD-R 102 in FIG. 1, which is in the middle of writing, where information is partially recorded (Partially Recorded disc, which is referred as a "partial CD-R", hereinbelow).
(3) A disc i.e. a CD-R 103 in FIG. 1, which is finished with writing and finally formatted to have the almost same format as the CD 104 after completing recording (Finalized Disc, it is referred as a "finalized CD-R", hereinbelow).
As shown in FIG. 1, in the finalized CD-R 103, the lead in area LIA, the program area PA and the lead out area LOA, are formatted in the same manner as the CD 104.
Information record and reproduction are generally performed by the recording and reproducing apparatus for the exclusive use with respect to the CD-R. The guiding groove is formed at the record track of the CD-R. This guiding groove is wobbled by the frequency which is generated by FM-modulating the conveyance wave by the data which indicates an absolute time (ATIP: Absolute Time In Pregroove).
The recording and reproducing apparatus of the CD-R is constituted to control the record and reproduction with respect to the blank CD-R and the partial CD-R in the middle of writing, while carrying out the track and spindle control by use of the guiding groove. As shown in FIG. 1, the PMA (Program Memory Area) as a domain of a temporary TOC which stores the record history of the record information LIA, is prepared in the inner circumference of the lead in area of the partial CD-R 102. The PCA (Power Calibration Area) to perform trial writing, in order to obtain a suitable record laser power for each disc, is also prepared in the inner circumference.
Three kinds of information is recorded in the PMA, as following.
Firstly, the start address and end address etc., of the record information recorded in the program area, are recorded. These are recorded by use of the same format as the TOC information recorded in the lead in area of the CD 104.
Secondly, the disc distinguishing information (option) is recorded, to which numeral information of 6 figures (6 digits) for disc distinguishing, is recorded depending on the necessity.
Thirdly, skip command information and skip canceling information are recorded, which are constituted to skip each record area indicated by the TNO specified at the time of disc reproduction, or a portion (time specification is possible) of the record area indicated by the TNO.
In this manner, the reason why the information as a temporary TOC is recorded to the PMA in the partial CD-R, is that the TOC information cannot be recorded to the lead in area until the record completion (finalization) is finally directed, since there is a possibility that information may be added to be written into the remaining program area. For this reason, the partial CD-R is kept in such a state that no information is written in the lead in area and the lead out area. Therefore, each area has remained in the mirror surface finished state. In order to finally make the format of the CD-R same as that of the CD by directing the finalization, the recording and reproducing apparatus of the CD-R records the predetermined information and the TOC information recorded in the PMA to the lead in area, as the sub-code. The recording and reproducing apparatus of the CD-R also records to the lead out area, the predetermined information indicating the area, as the sub-code. Accordingly, in the CD player, the reproduction of the finalized CD-R is made possible.
In this manner, the CD-R of write once read many type is provided. However, though the finalized CD-R can be reproduced in the ordinary CD player exclusive for the CD reproduction, the information in the partial CD-R on which the information is recorded up to the middle thereof, is not constituted to be reproduced by the CD player, although the reproducible information is stored in the program area thereof. This is because the CD player does not have the mechanism for accessing the PMA, although the TOC information is recorded in the PMA provided in the inner circumferential side of the lead in area in the partial CD-R, as mentioned above. The conventional CD player is not adapted to cope with the reading control of such a partial CD-R, so that a servo-control system thereof may run recklessly if it reads the lead in area and lead out area since these areas are still in the mirror surface finished state, a servo-control system may run recklessly if the conventional CD player reads these areas. The correspondence of reading control was not made in this manner.
As a countermeasure of this, it may be proposed to construct a CD player to have a mechanism to access the PMA, and mechanism for reading the guiding groove and controlling the tracking and spindle, as in the case of the CD-R recording and reproducing apparatus. However, it is not preferred in an economical sense relative to the effect, to provide such mechanisms only for the partial CD-R.
In case that the partial CD-R is reproduced by the CD player, the discrimination of the disc becomes necessary. The applicant of the present invention, has proposed a method of discrimination in the prior application (Japanese Patent Application Hei No.3-21205). However, by this discrimination method, it becomes necessary to provide a mechanism to detect the wobbling frequency of the guide groove, and the discrimination of the partial CD-R and the blank disc cannot be performed unless it performs an access until the most outer circumference in order to detect the RF signal from the inner circumference to the outer circumference of the optical disc.